Is Maushold even playable without veil?
Maushold's biggest limiting factor is that it has low defenses and needs its item slot, so cannot wear HDB, leaving it exceptionally frail. Its second biggest limiting factor is that Rocky Helmet is a good item already, leaving many balance teams with a hard counter to a Maushold sweep without even trying.
Its strength is a great speed tier, outrunning and OHKOing Ogerpon-W (or non-terastalized base Ogerpon) and anything slower, and the sheer power of Population Bomb:
252 Atk Technician Maushold Population Bomb (10 hits) vs. 244 HP / 36 Def Gliscor: 280-340 (79.5 - 96.5%) -- approx. 2HKO after Poison Heal
That's a neutral hit on Gliscor, a notorious physical fatty, without a Tidy Up boost. Getting a free turn to click Tidy Up is difficult, but the payoff is going nuclear:
+1 252 Atk Technician Maushold Population Bomb (10 hits) vs. 252 HP / 160+ Def Skarmory: 160-190 (47.9 - 56.8%) -- approx. 81.3% chance to 2HKO
Ho hum, a favorable chance to 2HKO a physical wall that resists the move. It's a 60% chance to 2HKO Dondozo, as well, so you can break the big lug if it hasn't Cursed up yet, or if you predict it switching in. If you're Tera Ghost to dodge the Body Press, all that Skarm (or Corv, they're interchangeable here) can do is Iron Defense up and get Encore'd into the move, meaning they aren't an answer.
Tera Ghost beats steel birds and can, depending on how many hazards it had to take, take a Crunch from ID/BP Zamazenta to click Tidy Up (to outspeed) and then Encore or Population Bomb it, depending on which contributes more. Tera Dark can kill offensive Gholdengo from full, and heavily chunk defense sets while surviving a +0 Make it Rain if hazards weren't fully stacked; it also forces a PP stall on CM Sinistcha, because Matcha Gotcha's healing isn't enough to survive two +1 Tera Dark Bites, giving the Maushold user the choice between trading Tidy Up PP for Strength Sap PP, or else just clicking Encore and switching out, having cleared hazards.
Of course, Tera Ghost never breaks the bulky ghosts, and Tera Dark never gets past the steel birds, and do not underestimate the difficulty of getting that free turn to Tidy Up while still having enough health to put in work afterwards - it's no good to get chunked to 20% and then picked off by priority, 75/70/75 bulk with no resistances does not take a hit well. It needs to be an early addition to the team to compensate for its weaknesses, but the payoff is there, and there's more ways to offset the vulnerability than just a veil team.